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Phobos (moon)
Phobos (; astronomical naming conventions, systematic designation: ) is the innermost and larger of the two moons of Mars, natural satellites of Mars, the other being Deimos (moon), Deimos. The two moons were discovered in 1877 by American astronomer Asaph Hall. It is named after Phobos (mythology), Phobos, the Greek mythology, Greek god of fear and panic, who is the son of Ares (Mars) and twin brother of Deimos (deity), Deimos. Phobos is a small, irregularly shaped object with a mean radius of . Phobos orbits from the Martian surface, closer to its Primary (astronomy), primary body than any other known Natural satellite, planetary moon. It is so close that it orbits Mars much faster than Mars rotates, and completes an orbit in just 7 hours and 39 minutes. As a result, from the surface of Mars it appears to rise in the west, move across the sky in 4 hours and 15 minutes or less, and set in the east, twice each Mars sol, Martian day. Phobos is one of the least reflective bodie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phobos (mythology)
Phobos ( grc, Φόβος, , Ancient Greek: "fear") is the god and personification of fear and panic in Greek mythology. Phobos was the son of Ares and Aphrodite, and the brother of Deimos. He does not have a major role in mythology outside of being his father's attendant.Hesiod, ''Theogony'933/ref> In Classical Greek mythology, Phobos exists as both the god of and personification of the fear brought by war. In Roman mythology, he has also been referred to as Pavor or Terror. Mythology Phobos was the son of Ares and Aphrodite. He mainly appears in an assistant role to his father and causes disorder in battle. In the ''Iliad'', he accompanied his father into battle along with the goddess Eris (discord) and his brother Deimos (Dread). In Hesiod's '' Shield of Herakles'', Phobos and Deimos accompany Ares into battle and remove him from the field once he is injured by Herakles. In Nonnus' '' Dionysiaca'', Zeus arms Phobos with lightning and Deimos with thunder to frighten Ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre Per Second
The metre per second is the unit of both speed (a scalar (physics), scalar quantity) and velocity (a Vector (mathematics and physics), vector quantity, which has direction and magnitude) in the International System of Units (SI), equal to the speed of a body covering a distance of one metre in a time of one second. The International System of Units, SI unit symbols are m/s, m·s−1, m s−1, or . Sometimes it is abbreviated as "mps". Conversions is equivalent to: : = 3.6 kilometres per hour, km/h (exactly) : ≈ 3.2808 feet per second (approximately) : ≈ 2.2369 miles per hour (approximately) : ≈ 1.9438 knot (unit), knots (approximately) 1 feet per second, foot per second = (exactly) 1 miles per hour, mile per hour = (exactly) 1 kilometres per hour, km/h = (exactly) Relation to other measures The benz, named in honour of Karl Benz, has been proposed as a name for one metre per second. Although it has seen some support as a practical unit, primarily from German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albedo
Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation. Surface albedo is defined as the ratio of Radiosity (radiometry), radiosity ''J''e to the irradiance ''E''e (flux per unit area) received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface. These factors vary with atmospheric composition, geographic location, and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravity, gravitationally bound system of the Sun and the objects that orbit it. It Formation and evolution of the Solar System, formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The solar mass, vast majority (99.86%) of the system's mass is in the Sun, with most of the Jupiter mass, remaining mass contained in the planet Jupiter. The four inner Solar System, inner system planets—Mercury (planet), Mercury, Venus, Earth and Mars—are terrest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Sol
Sol (borrowed from the Latin word for sun) is a solar day on Mars; that is, a Mars-day. A sol is the apparent interval between two successive returns of the Sun to the same meridian (sundial time) as seen by an observer on Mars. It is one of several units for timekeeping on Mars. A sol is slightly longer than an Earth day. It is approximately 24 hours, 39 minutes, 35 seconds long. A Martian year is approximately 668 sols, equivalent to approximately 687 Earth days or 1.88 Earth years. The sol was adopted in 1976 during the Viking Lander missions and is a measure of time mainly used by NASA when, for example, scheduling the use of the Mars rover. Length The average duration of the day-night cycle on Mars — i.e., a Martian day — is 24 hours, 39 minutes and 35.244 seconds, equivalent to 1.02749125 Earth days. The sidereal rotational period of Mars—its rotation compared to the fixed stars—is 24 hours, 37 minutes and 22.66 seconds. The solar day lasts longer because Mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Satellite
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'', a derivation from the Moon of Earth. In the Solar System, there are six planetary satellite systems containing 209 known natural satellites altogether. Seven objects commonly considered dwarf planets by astronomers are also known to have natural satellites: , Pluto, Haumea, , Makemake, , and Eris. , there are 442 other minor planets known to have natural satellites. A planet usually has at least around 10,000 times the mass of any natural satellites that orbit it, with a correspondingly much larger diameter. The Earth–Moon system is a unique exception in the Solar System; at 3,474 kilometres (2,158 miles) across, the Moon is 0.273 times the diameter of Earth and about of its mass. The next largest ratios are the Neptune–Tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary (astronomy)
A primary (also called a gravitational primary, primary body, or central body) is the main physical body of a gravitationally bound, multi-object system. This object constitutes most of that system's mass and will generally be located near the system's barycenter. In the Solar System, the Sun is the primary for all objects that orbit the star. In the same way, the primary of all satellites (be they natural satellites (moons) or artificial ones) is the planet they orbit. The term ''primary'' is often used to avoid specifying whether the object near the barycenter is a planet, a star, or any other astronomical object. In this sense, the word ''primary'' is always used as a noun. The center of mass is the average position of all the objects weighed by mass. The Sun is so massive that the Solar System's barycenter frequently lies very near the Sun's center but owing to the mass and distance of the gas giant planets, the Solar System's barycenter occasionally lies outside the Sun as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deimos (deity)
Deimos ( grc, Δεῖμος, , meaning “dread”) is the personal god of dread and Horror and terror, terror in Greek mythology. He was a son of Ares and Aphrodite, and the brother of Phobos (mythology), Phobos. Deimos served to represent the feelings of dread and terror that befell those before a battle, while Phobos personified feelings of fear and panic in the midst of battle. The god’s Interpretatio graeca, Roman equivalent was Formido or Metus. Mythology Deimos was the son of Ares and Aphrodite. He mainly appears in an assistant role to his father who causes disorder in armies. In the ''Iliad'', he accompanied his father, Ares, into battle along with the Goddess of Discord Eris (mythology), Eris and his brother Phobos (deity), Phobos (fear). In ''Shield of Heracles, Shield of Herakles'', Phobos and Deimos accompany Ares into battle and remove him from the field once he is injured by Heracles, Herakles. In Nonnus' ''Dionysiaca'', Zeus arms Phobos with lightning an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ares
Ares (; grc, Ἄρης, ''Árēs'' ) is the Greek god of war and courage. He is one of the Twelve Olympians, and the son of Zeus and Hera. The Greeks were ambivalent towards him. He embodies the physical valor necessary for success in war but can also personify sheer brutality and bloodlust, in contrast to his sister, the armored Athena, whose martial functions include military strategy and generalship. An association with Ares endows places, objects, and other deities with a savage, dangerous, or militarized quality. Although Ares' name shows his origins as Mycenaean, his reputation for savagery was thought by some to reflect his likely origins as a Thracian deity. Some cities in Greece and several in Asia Minor held annual festivals to bind and detain him as their protector. In parts of Asia Minor, he was an oracular deity. Still further away from Greece, the Scythians were said to ritually kill one in a hundred prisoners of war as an offering to their equivalent of Ares. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical cosmology, nature of the world, the lives and activities of List of Greek mythological figures, deities, Greek hero cult, heroes, and List of Greek mythological creatures, mythological creatures, and the origins and significance of the ancient Greeks' own cult (religious practice), cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of ancient Greece, and to better understand the nature of myth-making itself. The Greek myths were initially propagated in an oral tradition, oral-poetic tradition most likely by Minoan civilization, Minoan and Mycenaean Greece, Mycenaean singers starting in the 18th century BC; eventually the myths of the heroes of the Trojan War and its after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deimos (moon)
Deimos ( systematic designation: Mars II) is the smaller and outermost of the two natural satellites of Mars, the other being Phobos. Of similar composition to C and D-type asteroids, Deimos has a mean radius of and takes 30.3 hours to orbit Mars. Deimos is from Mars, much farther than Mars's other moon, Phobos. It is named after Deimos, the Ancient Greek god and personification of dread and terror. Discovery and etymology Deimos was discovered by Asaph Hall III at the United States Naval Observatory in Washington, D.C. on 12 August 1877, at about 07:48 UTC. Hall, who also discovered Phobos shortly afterwards, had been specifically searching for Martian moons at the time. The moon is named after Deimos, a figure representing dread in Greek mythology. The name was suggested by academic Henry Madan, who drew from Book XV of the ''Iliad'', where Ares (the Roman god Mars) summons Dread (Deimos) and Fear ( Phobos). Origin The origin of Mars's moons is unknown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moons Of Mars
The two moons of Mars are Phobos and Deimos. They are irregular in shape. Both were discovered by American astronomer Asaph Hall in August 1877 and are named after the Greek mythological twin characters Phobos (fear and panic) and Deimos (terror and dread) who accompanied their father Ares into battle. Ares, god of war, was known to the Romans as Mars. Compared to the Earth's Moon, the moons Phobos and Deimos are small. Phobos has a diameter of 22.2 km (13.8 mi) and a mass of 1.08 kg, while Deimos measures 12.6 km (7.8 mi) across, with a mass of 2.0 kg. Phobos orbits closer to Mars, with a semi-major axis of and an orbital period of 7.66 hours; while Deimos orbits farther with a semi-major axis of and an orbital period of 30.35 hours. History Early speculation Speculation about the existence of the moons of Mars had begun when the moons of Jupiter were discovered. When Galileo Galilei, as a hidden report about his having observed two bumps on the si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
